Data compressing apparatus

Abstract

A data compressing apparatus which can reduce a processing load associated to a data compressing process. The data compressing apparatus is used in a data transmitting apparatus for performing a data transmission, and includes a transmission mode selecting circuit for selecting the first transmission mode or second transmission mode in accordance with information indicating a kind of input data, a data compressing circuit for compressing the input data and transmitting it to a data output terminal, and a switch for allowing the input data to be transmitted to the data output terminal in accordance with the first transmission mode and allowing the input data to be transmitted to a data compressing circuit in accordance with the second transmission mode. The transmission mode is selected by the transmission mode selecting circuit on the basis of the signal indicative of the kind of input data. Whether the data compression is performed by the data compressing circuit or not is discriminated in accordance with the kind of input data. The load of the compressing process, therefore, can be reduced.

What is claimed is:  
     
         1 . A data compressing apparatus for use in a data transmitting apparatus for transmitting data, comprising: 
 transmission mode selecting means for selecting a first transmission mode or a second transmission mode in accordance with information indicating a kind of input data;    data compressing means for compressing said input data and transmitting it to a data output terminal; and    switching means for allowing said input data to be transmitted to said data output terminal in accordance with said first transmission mode and allowing said input data to be transmitted to said data compressing means in accordance with said second transmission mode.    
     
     
         2 . An apparatus according to    claim 1   , wherein the information indicating the kind of said input data is directly supplied as data independent of said input data to said transmission mode selecting means.  
     
     
         3 . An apparatus according to    claim 1   , wherein the information indicating the kind of said input data is additional information of said input data.  
     
     
         4 . An apparatus according to any one of    claim 1   , wherein the information indicating the kind of said input data includes information indicating whether said input data is compression data or not, and said transmission mode selecting means selects said first transmission mode when said input data is the compression data and selects said second transmission mode when said input data is not the compression data.  
     
     
         5 . An apparatus according to    claim 2   , wherein the information indicating the kind of said input data includes information indicating whether said input data is compression data or not, and said transmission mode selecting means selects said first transmission mode when said input data is the compression data and selects said second transmission mode when said input data is not the compression data.  
     
     
         6 . An apparatus according to claim to  3 , wherein the information indicating the kind of said input data includes information indicating whether said input data is compression data or not, and said transmission mode selecting means selects said first transmission mode when said input data is the compression data and selects said second transmission mode when said input data is not the compression data.  
     
     
         7 . An apparatus according to    claim 1   , wherein the information indicating the kind of said input data includes information indicating whether said input data is data having error resilience or not, and said transmission mode selecting means selects said first transmission mode when said input data is the data having the error resilience and selects said second transmission mode when said input data is data that kacks error resilience.  
     
     
         8 . An apparatus according to    claim 2   , wherein the information indicating the kind of said input data includes information indicating whether said input data is data having error resilience or not, and said transmission mode selecting means selects said first transmission mode when said input data is the data having the error resilience and selects said second transmission mode when said input data is data that lacks error resilience.  
     
     
         9 . An apparatus according to    claim 3   , wherein the information indicating the kind of said input data includes information indicating whether said input data is data having error resilience or not, and said transmission mode selecting means selects said first transmission mode when said input data is the data having error resilience and selects said second transmission mode when said input data is data that lacks error resilience.  
     
     
         10 . An apparatus according to    claim 1   , wherein the information indicating the kind of said input data includes information indicating whether or not said input data is compression data and information indicating whether or not said input data is data having error resilience, and said transmission mode selecting means selects said first transmission mode when said input data is one of data that is compressed and has error resilience, data that is compressed and lacks error resilience and data that is uncompressed and has error resilience, and selects said second transmission mode when said input data is data that is uncompressed and lacks error resilience.  
     
     
         11 . An apparatus according to    claim 2   , wherein the information indicating the kind of said input data includes information indicating whether or not said input data is compression data and information indicating whether or not said input data is data having error resilience, and said transmission mode selecting means selects said first transmission mode when said input data is one of data that is compressed and has error resilience, data that is compressed and lacks error resilience and data that is uncompressed and has error resilience, and selects said second transmission mode when said input data is data that is uncompressed and lacks error resilience.  
     
     
         12 . An apparatus according to    claim 3   , wherein the information indicating the kind of said input data includes information indicating whether or not said input data is compression data and information indicating whether or not said input data is data having error resilience, and said transmission mode selecting means selects said first transmission mode when said input data is one of data that is compressed and has error resilience, data that is compressed and lacks error resilience and data that is uncompressed and has error resilience, and selects said second transmission mode when said input data is data that is uncompressed and lacks error resilience.